JPH0761469A - Lid material - Google Patents

Abstract

PURPOSE:To provide a lid material of which the incineration is easy, and which has a microwave oven adaptability, and an excellent usability such as being jointly equipped with easy peelability and easy pierceability for straw for a lid of a container made of a plastic for liquid beverages, etc. CONSTITUTION:A lid member sheet is formed by laminating a plastic film substrate layer 1 and an easily peelable resin layer 2 with an adhesive layer 3 by the dry lamiante method, etc., and an incision 5 to make the piercing of a straw easier is provided only on the plastic film substrate layer 1 of the laminated sheet, for the constitution of a lid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lid material for a plastic container such as polystyrene resin, polypropylene resin or polyethylene resin, which is used particularly in the field of beverages such as liquids.

[0002]

2. Description of the Related Art Conventionally, plastic molded containers are
Yogurt, pudding, jelly, and other dessert foods, chilled fruit juice for distribution, liquid drinks such as coffee, cocoa, and milk drinks, or instant noodles, snack foods, and other food fields, including medical products, toiletry products, and industry. It is used in a wide range of fields such as food materials, and in particular, it is often used as a beverage container in the food industry. The lid used for these beverage containers is required to be completely sealed from the viewpoint of storability and hygiene of the contents, and in particular, a film or sheet-shaped lid is generally sealed by heat sealing. Is. In addition, more and more products are equipped with a spout or easy peeling for the convenience of use.

The structure of these lids varies depending on the application and use conditions of the container, such as hot filling, aseptic packaging, and the presence or absence of retort treatment. For example, the following structures are known. . Aluminum foil layer (thickness 20 μm or more) / thermoadhesive resin layer Aluminum foil layer (thickness 20 μm or more) / heat seal agent coating layer Paper layer / polyethylene layer / aluminum foil layer / polyethylene layer / hot melt layer (hereinafter polyethylene is PE) Heat-resistant resin film layer / adhesive or PE layer / aluminum foil layer / thermoadhesive resin layer Heat-resistant resin film layer / adhesive or PE layer / aluminum foil layer / easy peel resin layer (adhesive to olefin resin Blended with additives etc.) Aluminum foil layer / adhesive layer / biaxially stretched plastic film layer / thermoadhesive resin layer, etc.

[0004]

However, in the case of these constitutions, all of them contain aluminum foil, which makes it difficult to regenerate or recycle the resin, and there is a problem that burnt residue remains even when incinerated. . Also, depending on the contents of the container, you may want to warm it with a microwave oven before drinking.
Although it is possible to heat the lid material by peeling it off, if the sealing strength is strong, the lid material may not be completely peeled off and may remain at the mouth of the container. In such a case, if an aluminum foil is laminated on the lid material, there is a problem in that the aluminum is left over and a spark is generated when it is placed in a microwave oven so that the lid cannot be heated.

Furthermore, recently, from the various consumer preferences, it is desired that these film and sheet-like lid materials have the dual function of having easy peeling properties and at the same time making straws easy to pierce. Is coming out. For example, when the aluminum foil was removed to improve the incineration property and microwave oven suitability, a biaxially stretched plastic film having heat resistance and mechanical strength was used as a base material, and an easy peeling sealant was laminated on the base material. It can be configured,
In this case, the problem remains that the straw cannot be pierced as it is.

Therefore, the present invention improves the drawbacks of these lid materials, does not contain aluminum foil, is easy to incinerate, is suitable for a microwave oven, and has an easy peeling property and a straw piercing property. An object is to provide a lid material excellent in suitability for use.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present inventors have made various studies and as a result, as shown below, aluminum foil was removed from the constituent material of the lid material, and heat resistant plastic was used as the base material. Using a film, it has a structure in which an easy peeling resin is laminated as a sealant,
Only the plastic film substrate layer of the laminated sheet,
The present invention has been completed by finding a combination of material constitutions in which a notch for making a straw pierce easily can be inserted quickly and reliably.

That is, the invention of claim 1 is a lid material for a plastic container comprising a laminated sheet of a plastic film base material layer and an easy peeling resin layer, the lid material comprising metal such as aluminum foil. Not including, only the plastic film base layer of the laminated sheet is provided with a notch for facilitating the piercing of the straw, and has a lid material having both easy peeling property and easiness of piercing the straw.

Further, in the invention of claim 2, the plastic film substrate layer of the laminated sheet is formed of any one of a biaxially stretched polyester film, a biaxially stretched polyamide film, a polycarbonate film and a polybutylene terephthalate film. The lid member according to claim 1, wherein the lid member is provided.

As a method of making a cut only in the plastic film base material layer of the laminated sheet, carbon dioxide laser light is used, and the material and the laminated structure of the plastic film base material layer and the easy peelable resin layer are specified. By doing so, a stable cutting process is possible, and a lid material having both easy peeling property and easy straw piercing property is obtained.

The present invention will be described in detail below with reference to the drawings. 1 and 2 are schematic cross-sectional views showing one embodiment of the configuration of the lid member of the present invention. That is, FIG. 1 shows that a plastic film base layer 1 and an easy peeling resin layer 2 are laminated by an adhesive layer 3 by a dry laminating method or the like, and only the plastic film base layer 1 of the laminated sheet has a straw. Notch 5 to make it easier to pierce
It shows a configuration provided with.

In FIG. 2, a plastic film base layer 1 and an easy peelable resin layer 2 are laminated by a sandwich laminating method using a polyethylene layer 4, and a cut portion is formed only on the plastic film base layer 1 of the laminated sheet. 5 shows a configuration provided with 5.

3 (a), 3 (b) and 3 (c) are schematic plan views showing examples of the shape of the notch 5 provided in the plastic film base material layer 1 of the lid material of the present invention. The shapes of the cutouts (a), (b), and (c) are typical preferred patterns, and are not limited to these. The size of these cuts is usually approximately the same as or slightly larger than the diameter of the straw, which is suitable for easy alignment with the straw.

FIG. 4 is a schematic plan view showing an embodiment of the lid member of the present invention. That is, a structure is shown in which a cut portion 5 for making it easier to pierce a straw is provided in a part of the lid member 6 punched out in a circle having the knob piece 7.

In each of the lid members, a pattern layer may be provided by printing on one surface of the plastic film substrate (usually the surface on which the easy peel resin is laminated), or if necessary. It is free to provide an uneven pattern or the like on at least one surface of the lid material by embossing or the like.

Next, the constituent materials of each layer will be described in detail. (Plastic film base material layer) In the lid material of the present invention, this layer is a base material layer, and the main performances required are good printability and mechanical strength such as tensile strength and tear strength. Basically, it is excellent and resistant to heat during heat sealing. And, in particular, from the point of making a cut by a carbon dioxide laser beam, it must be a material that can absorb this, generate heat, melt, mist, and be removed.

A film which does not contain a polyolefin component is preferable as the film satisfying such performances and conditions, and examples thereof include a biaxially stretched polyester film, a biaxially stretched polyamide film, a polycarbonate film and a polybutylene terephthalate film.
Of these, biaxially stretched polyethylene terephthalate film (hereinafter PET), biaxially stretched nylon film (hereinafter ON), polycarbonate film (hereinafter PC), polybutylene terephthalate film (hereinafter PBT), etc. are particularly preferable. . Further, the thickness of these films is appropriately in the range of 5 μm to 50 μm.

(Easy Peelable Resin Layer) The composition of the easy peelable resin used for the sealant of the lid material is slightly different depending on the material of the target plastic container. The lid material of the present invention mainly targets containers made of polystyrene resin and containers made of polyolefin resin such as polypropylene resin and polyethylene resin. Therefore, for the former polystyrene-based resin container, for example, a mixture of polyolefin and styrene-based resin, or a composition in which a copolymer of polyolefin and styrene is blended can be used. For the resin container, a composition mainly composed of an ethylene-vinyl acetate copolymer, a polyolefin different from the polyolefin of the container, or a blend resin of the same kind of polyolefin as the polyolefin can be used.
The composition containing ethylene-vinyl acetate copolymer as a main component can also be used for the former polystyrene resin container.

What should be considered here is that the lid material of the present invention is composed of a laminate of a plastic film base material layer and an easy peeling resin layer as a sealant, and only the plastic film base material layer is carbonated. The point is to make a cut with a gas laser beam. As explained in the previous section, we selected a resin that is easy to remove by heating with laser light for the plastic film substrate layer on the outside of the lid material, but for the easy peeling resin layer, on the contrary, the heating effect is low. Resins are preferred. In this respect, polyolefin-based resins such as polyethylene easily transmit carbon dioxide gas laser light and have a low heat-generating effect, so the above-mentioned easy-peel resin containing a relatively large amount thereof is suitable.

As a method for laminating the plastic film base material layer and the easy peeling resin layer, if the sandwich laminating method using polyethylene as shown in FIG. 2 is adopted, the plastic film base material layer and the easy peeling property are adopted. Since the polyethylene layer is inserted between the resin layer and the resin layer, the structure is more preferable. Even when laminated by the dry laminating method, not only the easy-peel resin alone to the plastic film substrate layer, but also the easy-peel resin layer may be co-extruded with the polyolefin resin and the easy-peel resin as necessary. A more preferable lid material sheet can be obtained by forming the above-mentioned two layers, or three layers in which an intermediate layer is further added, and by laminating the plastic film base material layer and the surface of the polyolefin resin layer. The thickness of this easy peeling resin layer is 20 μm
A range of 150 μm is suitable.

When a carbon dioxide gas laser beam is applied to the lid material sheet of the present invention formed from the above-mentioned material to process the notch for piercing the straw, the laser light passes through the mask having the notch pattern and the lid material sheet is cut. By irradiating from the plastic film base material layer side, it is possible to process only the plastic film base material layer.

[0022]

As described above, the lid material of the present invention comprises a laminated sheet of a plastic film substrate layer and an easy peeling resin layer, and only the plastic film substrate layer of the laminated sheet is irradiated with carbon dioxide laser light. It is a lid material for a plastic container, which is provided with an easy piercing portion for a straw by making a notch. Therefore, the lid material does not include a metal layer such as aluminum foil in the composition, is easy to incinerate after use, does not leave burnt residue, etc. It can be heated in a microwave oven, and the lid material can be easily peeled off, or a straw can be pierced into the lid material for use.

Further, the plastic film substrate layer and the easy peeling resin layer are laminated by irradiating carbon dioxide gas laser light so as to be divided into a resin layer which easily generates heat, melts and becomes a mist and a resin layer which transmits and is hard to generate heat. Therefore, when processing the easily pierced portion (cut) of the straw, only the plastic film base material layer is removed according to the mask pattern for cutting, and the easy peeling resin layer remains without being removed. Therefore, the strength of the cut portion does not become too weak, the sealing property is sufficiently maintained, and the straw can be easily pierced. The cutting process by irradiation of this carbon dioxide laser light is high speed,
In addition, since the depth can be made uniform, quality accuracy and productivity are improved.

[0024]

The present invention will be described in detail below with reference to examples. (Example 1) As a lid material for a container made of a polyolefin resin, a plastic film substrate layer was formed with a P layer having a thickness of 12 μm.
ET [E-5100 manufactured by Toyobo Co., Ltd.] is used, and CMPS 0 having a thickness of 80 μm is formed on the easy peelable resin layer.
A 09 (resin composition mainly composed of ethylene-vinyl acetate copolymer resin) film (manufactured by Tohcello Chemical Co., Ltd.) was dry-laminated with a two-component curing type urethane adhesive to obtain a laminated sheet.

Next, a carbon dioxide laser light irradiator [Shibuya Kogyo Co., Ltd. Model N] was applied to a part of this laminated sheet.
o.920-LB pulse oscillation type], a carbon dioxide gas laser beam having a wavelength of 10.6 μm is passed through a die-cut stainless steel aperture mask in the pattern shown in FIG. Irradiation was performed by converging with a lens and feeding from the plastic film base material layer side so that the pitch of the irradiation portion was 90 mm. The distance ratio between the aperture mask and the converging lens and between the converging lens and the laminated sheet was set to 4.5: 1, and the irradiation time was 0.1 μsec / s.
It was hot.

In this way, a laminated sheet was prepared in which the straw piercing notches having the pattern shown in FIG. 3 (a) were provided only in the plastic film base layer, and this sheet was formed into a circle with a diameter of 80 mm and a circle A lid material of Example 1 was obtained by punching with a punching die having a knob on its part so as to include the above-mentioned notch in a circle. Structure: PET layer (12 μm) / adhesive layer (3 μm) / C
MPS 009 layer (80 μm) (total sheet thickness 95 μ
m)

(Embodiment 2) In the construction of Embodiment 1, only the plastic film base material layer is turned on with a thickness of 15 μm.
In place of [Emblem Unitika Co., Ltd.], the rest was processed in the same manner as in Example 1 to obtain a lidding material for a polyolefin resin container of Example 2. Structure: ON layer (15 μm) / adhesive layer (3 μm) / CM
PS 009 layer (80 μm) (total sheet thickness 98 μm)

(Embodiment 3) In the construction of Embodiment 1, the PET (12 μm) of the plastic film substrate layer and the CMPS 009 (80 μm) of the easy peelable resin layer are laminated by PE (thickness) instead of dry lamination. 2
0 μm) was used instead of the sandwich laminating method by an extruder, and the lamination was performed in the same manner as in Example 1 to obtain a lid material for a polyolefin resin container of Example 3. An isocyanate-based anchor coating agent was applied to the laminated surface of the plastic film base material, and low density polyethylene (hereinafter referred to as LDP) was used as sand PE for the intermediate layer.
E) Laminated using [Mirason 16P manufactured by Mitsui Petrochemical Industry Co., Ltd.]. Structure: PET layer (12 μm) / LDPE layer (20 μm)
/ CMPS 009 layer (80 μm) (total sheet thickness 11
2 μm)

(Embodiment 4) PET (12 μm) of the plastic film base material layer in the constitution of the lid material of Embodiment 3 is used.
Only polycarbonate film (PC) (30 μm)
In place of [AA30 manufactured by Teijin Kasei Co., Ltd.], the rest was processed in the same manner as in Example 3 to obtain a lid material for a polyolefin resin container of Example 4. Structure: PC layer (30 μm) / LDPE layer (20 μm) /
CMPS 009 layer (80 μm) (total sheet thickness 130
μm)

Example 5 A plastic film base material layer having a thickness of 1 was used as a lid material for a polystyrene resin container.
5μm ON is used, the following three layers of co-extrusion sheet (total thickness 80μm) are used for the easy peeling resin layer,
A laminated sheet was prepared by bonding ON and the linear low-density polyethylene (hereinafter LLDPE) surface of the three-layer coextrusion sheet by a dry lamination method using a two-component curing type urethane adhesive. Subsequently, the laminated sheet was subjected to a cutting process and a punching process using a carbon dioxide gas laser beam under the same conditions as in Example 1 to obtain a lid material of Example 5.

Easy peeling resin layer (extrusion of three layers)
Structure of sheet (first layer) LLDPE [Ultzex 2022L, manufactured by Mitsui Petrochemical Industry Co., Ltd.] (thickness: 45 μm) (second layer) LLDPE (Ultzex 2022L) 50 parts by weight Styrene / butadiene block copolymer [ Asaflex 810 manufactured by Asahi Kasei Kogyo Co., Ltd.] 50 parts by weight The above two kinds of blend resins (thickness 20 μm). (Third layer) Easy peeling resin LLDPE (Ultox 2022L) 30 parts by weight Styrene-butadiene elastomer (hereinafter referred to as SBR)
[Tuftec H1041 Asahi Kasei Co., Ltd.] 10 parts by weight High-impact polystyrene (hereinafter HIPS) [Stylon 475DY Asahi Kasei Co., Ltd.] 30 parts by weight Styrene-butadiene block copolymer [Asaflex 810 Asahi Kasei Co., Ltd.] ] 30 parts by weight The above-mentioned four kinds of blend resins (thickness 15 μm). [The total thickness of the three layers is 80 μm]

Structure: ON layer (15 μm) / adhesive layer (3
μm) / LLDPE layer (45 μm) / LLDPE / styrene-butadiene block copolymer layer (20 μm) / L
LDPE / SBR / HIPS / styrene-butadiene block copolymer layer (15 μm) (total sheet thickness 98 μ
m)

(Embodiment 6) In the construction of the lid material of Embodiment 5, only the plastic film substrate layer is turned on (15 μm) and the PBT film [VALOX P with a thickness of 25 μm is used.
KG1530 manufactured by Japan GE Plastics Co., Ltd., which was formed by a T-die], and otherwise processed in the same manner as in Example 5 to obtain a lid material for a polystyrene resin container of Example 6. Structure: PBT layer (25 μm) / adhesive layer (3 μm) / L
LDPE layer (45 μm) / LLDPE / styrene-butadiene block copolymer layer (20 μm) / LLDPE /
SBR / HIPS / styrene-butadiene block copolymer layer (15 μm) (total sheet thickness 108 μm)

(Example 7) In the constitution of the lid material of Example 5, the easy peelable resin layer is not a three-layer co-extruded sheet, but a second blended resin layer of LLDPE and styrene-butadiene block copolymer. 2 layers of coextruded sheet (except for the thickness of the first layer LLDP in Example 5)
The E layer is 45 μm, and the easy peeling resin of the third layer is 35 μm.
μm was formed in two layers), and the other processes were performed in the same manner as in Example 5 to prepare a lid material for the polystyrene resin container of Example 7. Structure: ON layer (15 μm) / adhesive layer (3 μm) / LL
DPE layer (45 μm) / LLDPE / SBR / HIPS
-Styrene-butadiene block copolymer layer (35μ
m) (total sheet thickness 98 μm)

(Embodiment 8) In the constitution of the lid member of Embodiment 5, the easy peeling resin layer is not a three-layer co-extrusion sheet, but the easy peeling resin layer used as the third layer is 70 μm thick as a single layer. In place of the sheet formed into the film described above, this was laminated with ON (15 μm) of the plastic film base material layer with a two-component curing type urethane adhesive by a dry lamination method to prepare a laminated sheet for a lid material. Using this laminated sheet, cutting and punching by carbon dioxide gas laser irradiation were carried out in the same manner as in Example 5 to prepare a lid material for a polystyrene resin container of Example 7. Structure: ON layer (15 μm) / adhesive layer (3 μm) / LL
DPE / SBR / HIPS / styrene-butadiene block copolymer layer (70 μm) (total sheet thickness 88 μm)

(Comparative Example 1) In the constitution of the lid material of Example 1, PET (1
2 μm) was replaced with an OPP having a thickness of 25 μm, and the other processes were performed in the same manner as in Example 1 to prepare a lid material for a polyolefin resin container of Comparative Example 1. Structure: OPP layer (25 μm) / adhesive layer (3 μm) / C
MPS 009 layer (80 μm) (total sheet thickness 108 μm
m)

(Comparative Example 2) In the structure of the lid member of Example 5, ON (15) used in the plastic film base material layer was used.
μm) is replaced by a 25 μm thick OPP, and others are
The same processing as in Example 5 was carried out to prepare a lid material for a polystyrene resin container of Comparative Example 2. Structure: OPP layer (25 μm) / adhesive layer (3 μm) / L
LDPE layer (45 μm) / LLDPE / styrene-butadiene block copolymer layer (20 μm) / LLDPE /
SBR / HIPS / styrene-butadiene block copolymer layer (15 μm) (total sheet thickness 108 μm)

(Test and Evaluation Results) Using the lid materials of Examples 1 to 8 and Comparative Examples 1 and 2 prepared as described above as samples, the following four items were tested, and the results are shown in Table 1. Indicated. (1) Machinability of Cuts by Irradiation with Carbon Dioxide Laser Light The machinability of the easy-peel resin layer was evaluated as to whether or not only the plastic film base layer could be efficiently removed. (2) Heat-sealability Each sample is subjected to a ring sealer, and the target container, that is, a polypropylene container in the case of a lid material for a polyolefin resin container, a lid material for a polystyrene resin container Was heat-sealed in a HIPS container, and its adhesiveness and appearance were evaluated.

(3) Easy peeling property The easy peeling property was evaluated by grasping the picking portion of the lid material of each lidded container prepared by the above heat sealability test by hand, pulling it up in the direction of 90 ° and peeling it off. . (4) Easy piercing of straw Using a plastic straw whose tip is cut obliquely to the cut portion of the lid material of each lidded container created in the heat sealability test, piercing by hand is easy. It was evaluated whether or not it can be opened.

[0040]

[Table 1] ◯: Good. Δ: Practically acceptable although somewhat inferior X: Bad. *: Can be heat-sealed, but wavy easily.

[0041]

As described above, the lid member of the invention of claim 1 is a lid member for a plastic container comprising a laminated sheet of a plastic film base material layer and an easy peelable resin layer, The lid material does not contain a metal such as aluminum foil, and only the plastic film base layer of the laminated sheet is provided with a notch for facilitating the piercing of the straw, and has both easy peelability and easiness of piercing the straw. It is a lid material characterized by that. By adopting such a configuration, it is easy to incinerate after use and does not leave burnt residue, and when used, it can be heated in a microwave oven as it is if a part of the lid material is opened. In addition, it is possible to provide a lid material excellent in usability in that the entire lid material can be easily peeled off and that the lid material can be pierced with a straw and used freely. In addition, carbon dioxide laser light can be used for cutting to make it easier to pierce the straw, and only the plastic film substrate layer can be processed at high speed and with stability, so the strength of the cut may become too weak. In addition, the sealing property is sufficiently maintained, and the lid material having excellent quality accuracy can be efficiently produced.

The lid material of the invention of claim 2 is the lid material of the invention of claim 1, wherein the plastic film substrate layer of the laminated sheet is a biaxially stretched polyester film, a biaxially stretched polyamide film, a polycarbonate film, One of the butylene terephthalate films. By adopting such a configuration, in addition to the effect obtained by the invention of claim 1, the cutting process by the carbon dioxide gas laser beam becomes easier and the range of processing conditions becomes wider, so that the lid of stable quality is obtained. The material can be provided with higher productivity.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a first embodiment of the configuration of a lid member of the present invention.

FIG. 2 is a schematic cross-sectional view showing a second embodiment of the configuration of the lid member of the present invention.

3 (a), (b) and (c) are schematic plan views each showing an example of the shape of a notch portion for straw piercing provided in the plastic film base material layer of the lid material of the present invention. is there.

FIG. 4 is a schematic plan view showing an embodiment of the lid member of the present invention.

[Explanation of symbols]

1 Plastic Film Base Layer 2 Easy Peeling Resin Layer 3 Adhesive Layer 4 Polyethylene Layer 5 Notch 6 Lid 7 Knob Piece

Claims (2)

[Claims] 1. A lid material for a plastic container comprising a laminated sheet of a plastic film substrate layer and an easy peelable resin layer, wherein the lid material does not contain a metal such as aluminum foil and the plastic of the laminated sheet. A lid material having notches for making it easier to pierce the straw only in the film base layer, and having both easy peeling property and easiness of piercing the straw. 2. The plastic film substrate layer of the laminated sheet is composed of any one of a biaxially oriented polyester film, a biaxially oriented polyamide film, a polycarbonate film and a polybutylene terephthalate film. The lid member according to Item 1.